It is generally known to provide needle latch detectors on circular knitting machines for indicating the improper positioning of the latches, which condition usually occurs when a stitch loop is not present on the needle to move the latch to an open position. However, the prior known types of latch detectors have not been widely used because they are expensive and/or difficult to maintain in the proper operative position because vibration from the knitting machine will frequently trip the latch detector. Also, if the sensitivity of the latch detector is set to prevent false detection, there is a possibility of damage to the needle latch when it engages the latch detector.